TV receiver with automatic RF/baseband signal

摘要

A receiver includes a video switch operated by a controller for selecting antenna or auxiliary (baseband) video signals for display. When placed in a "VCR" operating mode the controller first selects the auxiliary input for display. If a video signal is not present at the auxiliary input the controller causes the switch to select the output of a tuner thereby providing an automatic signal search to locate the VCR signal which may be applied to either of the antenna and auxiliary inputs. An extension of the search includes tuning the tuner to channel 3 and, if no signal is found, tuning the tuner to channel 4. Upon failure to find an active video signal on either channel the tuner is returned to the last channel received prior to selecting the VCR mode of operation thereby releaving the user of both mode selection and channel selection requirements for locating the VCR signal.